Having saved two match points to take home the Tokyo title last weekend, Black and Mirza have strengthened their aura of invincibility with three comfortable wins in the Chinese capital. The latest of these came against Chan Yung-Jan and Zheng Jie, who after some early resistance were swept aside, 64 61.

Twenty-four hours earlier Chan and Zheng had knocked out No.3 seeds Ashleigh Barty and Casey Dellacqua, and when they broke Black in the third game of the match another upset looked on the cards.

However, after a surrendering the break and then the set it was one-way traffic with Black and Mirza wrapping up victory after little over an hour on court.

Chan and Zheng, who had points for a 5-3 and 5-4 lead, were left ruing their missed opportunities. "We started well and had a 4-2 lead in the first set," Zheng said. "The first set we played was really close and we had many chances in the games at the end, but at that point sometimes you need a little bit of luck and things to go your way.

"Then after we lost the first set, I think that Sania and Cara got a lot more confident and on their current form it's not easy against them."